[PATCH v2 2/2] media: cedrus: Implement runtime PM

[Samuel Holland <samuel@sholland.org>]

This allows the VE clocks and PLL_VE to be disabled most of the time.
A runtime PM reference is held while streaming.

Originally-by: Jernej Škrabec <jernej.skrabec@gmail.com>
Signed-off-by: Samuel Holland <samuel@sholland.org>
---

v2: moved PM reference to cedrus_{start,stop}_streaming, based on an
    earlier patch by Jernej Skrabec. Removes the need for autosuspend.
    I tested this with running 2x v4l2-request-test in parallel.

---
 drivers/staging/media/sunxi/cedrus/cedrus.c   |   7 ++
 .../staging/media/sunxi/cedrus/cedrus_hw.c    | 106 ++++++++++++------
 .../staging/media/sunxi/cedrus/cedrus_hw.h    |   3 +
 .../staging/media/sunxi/cedrus/cedrus_video.c |  33 ++++--
 4 files changed, 104 insertions(+), 45 deletions(-)

diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.c b/drivers/staging/media/sunxi/cedrus/cedrus.c
index 05a85517ff60..bc27f9430eeb 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus.c
@@ -16,6 +16,7 @@
 #include <linux/platform_device.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/pm.h>
 
 #include <media/v4l2-device.h>
 #include <media/v4l2-ioctl.h>
@@ -551,12 +552,18 @@ static const struct of_device_id cedrus_dt_match[] = {
 };
 MODULE_DEVICE_TABLE(of, cedrus_dt_match);
 
+static const struct dev_pm_ops cedrus_dev_pm_ops = {
+	SET_RUNTIME_PM_OPS(cedrus_hw_suspend,
+			   cedrus_hw_resume, NULL)
+};
+
 static struct platform_driver cedrus_driver = {
 	.probe		= cedrus_probe,
 	.remove		= cedrus_remove,
 	.driver		= {
 		.name		= CEDRUS_NAME,
 		.of_match_table	= of_match_ptr(cedrus_dt_match),
+		.pm		= &cedrus_dev_pm_ops,
 	},
 };
 module_platform_driver(cedrus_driver);
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
index daf5f244f93b..1744e6fcc999 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
@@ -19,6 +19,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/interrupt.h>
 #include <linux/clk.h>
+#include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/reset.h>
 #include <linux/soc/sunxi/sunxi_sram.h>
@@ -140,6 +141,64 @@ static irqreturn_t cedrus_irq(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+int cedrus_hw_suspend(struct device *device)
+{
+	struct cedrus_dev *dev = dev_get_drvdata(device);
+
+	reset_control_assert(dev->rstc);
+
+	clk_disable_unprepare(dev->ram_clk);
+	clk_disable_unprepare(dev->mod_clk);
+	clk_disable_unprepare(dev->ahb_clk);
+
+	return 0;
+}
+
+int cedrus_hw_resume(struct device *device)
+{
+	struct cedrus_dev *dev = dev_get_drvdata(device);
+	int ret;
+
+	ret = clk_prepare_enable(dev->ahb_clk);
+	if (ret) {
+		dev_err(dev->dev, "Failed to enable AHB clock\n");
+
+		return ret;
+	}
+
+	ret = clk_prepare_enable(dev->mod_clk);
+	if (ret) {
+		dev_err(dev->dev, "Failed to enable MOD clock\n");
+
+		goto err_ahb_clk;
+	}
+
+	ret = clk_prepare_enable(dev->ram_clk);
+	if (ret) {
+		dev_err(dev->dev, "Failed to enable RAM clock\n");
+
+		goto err_mod_clk;
+	}
+
+	ret = reset_control_reset(dev->rstc);
+	if (ret) {
+		dev_err(dev->dev, "Failed to apply reset\n");
+
+		goto err_ram_clk;
+	}
+
+	return 0;
+
+err_ram_clk:
+	clk_disable_unprepare(dev->ram_clk);
+err_mod_clk:
+	clk_disable_unprepare(dev->mod_clk);
+err_ahb_clk:
+	clk_disable_unprepare(dev->ahb_clk);
+
+	return ret;
+}
+
 int cedrus_hw_probe(struct cedrus_dev *dev)
 {
 	const struct cedrus_variant *variant;
@@ -236,42 +295,17 @@ int cedrus_hw_probe(struct cedrus_dev *dev)
 		goto err_sram;
 	}
 
-	ret = clk_prepare_enable(dev->ahb_clk);
-	if (ret) {
-		dev_err(dev->dev, "Failed to enable AHB clock\n");
-
-		goto err_sram;
-	}
-
-	ret = clk_prepare_enable(dev->mod_clk);
-	if (ret) {
-		dev_err(dev->dev, "Failed to enable MOD clock\n");
-
-		goto err_ahb_clk;
-	}
-
-	ret = clk_prepare_enable(dev->ram_clk);
-	if (ret) {
-		dev_err(dev->dev, "Failed to enable RAM clock\n");
-
-		goto err_mod_clk;
-	}
-
-	ret = reset_control_reset(dev->rstc);
-	if (ret) {
-		dev_err(dev->dev, "Failed to apply reset\n");
-
-		goto err_ram_clk;
+	pm_runtime_enable(dev->dev);
+	if (!pm_runtime_enabled(dev->dev)) {
+		ret = cedrus_hw_resume(dev->dev);
+		if (ret)
+			goto err_pm;
 	}
 
 	return 0;
 
-err_ram_clk:
-	clk_disable_unprepare(dev->ram_clk);
-err_mod_clk:
-	clk_disable_unprepare(dev->mod_clk);
-err_ahb_clk:
-	clk_disable_unprepare(dev->ahb_clk);
+err_pm:
+	pm_runtime_disable(dev->dev);
 err_sram:
 	sunxi_sram_release(dev->dev);
 err_mem:
@@ -282,11 +316,9 @@ int cedrus_hw_probe(struct cedrus_dev *dev)
 
 void cedrus_hw_remove(struct cedrus_dev *dev)
 {
-	reset_control_assert(dev->rstc);
-
-	clk_disable_unprepare(dev->ram_clk);
-	clk_disable_unprepare(dev->mod_clk);
-	clk_disable_unprepare(dev->ahb_clk);
+	pm_runtime_disable(dev->dev);
+	if (!pm_runtime_status_suspended(dev->dev))
+		cedrus_hw_suspend(dev->dev);
 
 	sunxi_sram_release(dev->dev);
 
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_hw.h b/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
index 604ff932fbf5..45f641f0bfa2 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
@@ -22,6 +22,9 @@ void cedrus_engine_disable(struct cedrus_dev *dev);
 void cedrus_dst_format_set(struct cedrus_dev *dev,
 			   struct v4l2_pix_format *fmt);
 
+int cedrus_hw_suspend(struct device *device);
+int cedrus_hw_resume(struct device *device);
+
 int cedrus_hw_probe(struct cedrus_dev *dev);
 void cedrus_hw_remove(struct cedrus_dev *dev);
 
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_video.c b/drivers/staging/media/sunxi/cedrus/cedrus_video.c
index ed3f511f066f..16d82309e7b6 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_video.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_video.c
@@ -13,6 +13,8 @@
  * Marek Szyprowski, <m.szyprowski@samsung.com>
  */
 
+#include <linux/pm_runtime.h>
+
 #include <media/videobuf2-dma-contig.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-ioctl.h>
@@ -450,12 +452,24 @@ static int cedrus_start_streaming(struct vb2_queue *vq, unsigned int count)
 		return -EINVAL;
 	}
 
-	if (V4L2_TYPE_IS_OUTPUT(vq->type) &&
-	    dev->dec_ops[ctx->current_codec]->start)
-		ret = dev->dec_ops[ctx->current_codec]->start(ctx);
+	if (V4L2_TYPE_IS_OUTPUT(vq->type)) {
+		ret = pm_runtime_get_sync(dev->dev);
+		if (ret < 0)
+			goto err_cleanup;
 
-	if (ret)
-		cedrus_queue_cleanup(vq, VB2_BUF_STATE_QUEUED);
+		if (dev->dec_ops[ctx->current_codec]->start) {
+			ret = dev->dec_ops[ctx->current_codec]->start(ctx);
+			if (ret)
+				goto err_pm;
+		}
+	}
+
+	return 0;
+
+err_pm:
+	pm_runtime_put(dev->dev);
+err_cleanup:
+	cedrus_queue_cleanup(vq, VB2_BUF_STATE_QUEUED);
 
 	return ret;
 }
@@ -465,9 +479,12 @@ static void cedrus_stop_streaming(struct vb2_queue *vq)
 	struct cedrus_ctx *ctx = vb2_get_drv_priv(vq);
 	struct cedrus_dev *dev = ctx->dev;
 
-	if (V4L2_TYPE_IS_OUTPUT(vq->type) &&
-	    dev->dec_ops[ctx->current_codec]->stop)
-		dev->dec_ops[ctx->current_codec]->stop(ctx);
+	if (V4L2_TYPE_IS_OUTPUT(vq->type)) {
+		if (dev->dec_ops[ctx->current_codec]->stop)
+			dev->dec_ops[ctx->current_codec]->stop(ctx);
+
+		pm_runtime_put(dev->dev);
+	}
 
 	cedrus_queue_cleanup(vq, VB2_BUF_STATE_ERROR);
 }
-- 
2.24.1